Otters are rare and threatened in China, but both research and conservation efforts on this specialized group of mammals are largely overlooked. To provide baseline information on the current conservation status of otters in coastal Guangdong Province, we conducted rapid otter surveys using semi-structured interviews, transects, camera-trapping surveys, and a molecular study of the coastal islands of Zhuhai City between September 2016 and March 2017. Data collected suggested a dramatic decline of otter populations and the local extirpation of otters was reported on several islands. The discovery of a remnant population of the Eurasian otter (Lutra lutra) on Hengqin Island provides hopes for the recovery of this species in South China. Nonetheless, the future of Hengqin’s otter is at stake due to the rapid urbanization of suitable habitats for economic development. To ensure its continual survival, critical habitats on Hengqin Island should be strictly protected as soon as possible. Furthermore, systematic, otter-specific surveys should be conducted in other coastal areas of China, to best devise a national otter conservation plan.